What helps us hear and stay balanced? Many people are surprised to find that they are very much connected. This is because the two functions share the same nerve pathway to the brain, known as the vestibulocochlear nerve. While the two are connected they both serve different functions: One part strictly for hearing while the other part is devoted to reporting the position and plane of our head to our brain. However, all too often if something goes wrong in either the vestibular system (devoted to balance) or auditory system, it can affect the other. For instance if you are experiencing dizziness, vertigo or ringing in the ears (tinnitus) it could signal something wrong within the inner ear.
To better understand the connection between the inner ear and the brain, scientists at Harvard Medical School recently identified the protein that plays an interictal role in hearing and maintaining balance. This protein called TMC1 may pave the way for new research and discoveries in the treatment for hearing loss and chronic balance issues.
Understanding the Auditory System
We collect sound with our outer ear, but the process is not completed until sound reaches our brain. It’s a long journey, which is amazingly complex, but it all occurs in less than a second.
- Outer ear: the process of hearing begins with the most visible part of the ear—the part that sticks out, made of cartilage, and collects sound from the environment. From here it is sent to the middle ear.
- Middle ear: within the middle ear, sound is amplified by the eardrum which in turn triggers the ossicles – three small bones, the smallest in our entire body. The ossicles work with the eardrum to send soundwaves into the inner ear.
- Inner ear: the inner ear holds a tiny snail shaped organ filled with fluid and thousands of hairlike cells called stereocilia. The stereocilia are triggered by vibrations of the fluid of the cochlea. As it receives these fluid vibrations the stereocilia transform them into electrical impulses which can be interpreted by the auditory cortex of the brain. This is where we truly listen and comprehend sound
Understanding Auditory Conversion
While scientists have come to understand the process of hearing, for years they have been puzzled by the actual process which allows the conversion from soundwave to electrical impulse, particularly on a molecular level. While it was understood that proteins on the membranes of stereocilia created tiny pores which were responsible for opening and closing as sound is processed, they didn’t understand the exact protein that facilitated this process. However, now scientists know the protein which manages this influx of electrically charged ions aiding in electrical signals to the brain through nerve cells.
The Discovery of TMC1: The Protein Supporting Hearing and Balance
First identified in the inner ear in a 2002 study, TMC1 is now understood to be the protein responsible for transforming audio signals into electrical impulses as well as communicating head position to the brain. A 2011 study further revealed that the TMC1 protein was essential for the process of hearing; however this 2018 Harvard based study, was able to isolate and further identify the role of TMC1!
TMC1 proteins combine to form pores on the membranes of hair cells. Researchers recreated this protein in the form of amino acids and then altered each amino acid in mice. They then observed and evaluated how each change of amino acid impacted the flow of ions through the pores in response to sound in test subjects.
Based on this research they were able to confidently identify the way sound waves are converted into electrical signals. For people with hearing loss, this discovery may help to illuminate genes that are linked to genetically caused hearing loss. Scientists hope to develop therapies and treatments for people with hearing issues related to the TMC1 gene.
Prioritize Your Hearing Health
This breakthrough is significant for people with hearing loss and raises hope for the future. However, for now the most effective way to treat hearing loss is with the use of hearing aids. Hearing aids can improve communication with loved ones, mobility, cognitive function as we age and so much more. To find out if hearing aids are right for you, don’t hesitate to contact us today to schedule your next hearing exam!